How manual electronic measuring devices ensure accuracy and safety for brake fluids
The use of manual electronic measuring devices to assess the water content and quality of brake fluids is becoming increasingly popular. Owing to the manual nature of their operation, it is crucial to ensure that the readings from these devices are accurate. As these devices have become more widely available on the internet, their quality has often diminished, with more misleading results being recorded. This can be extremely dangerous, as faulty results from electronic brake fluid testers can pose a significant risk to road safety.
There have been cases of these devices incorrectly reporting that fresh bottles of brake fluid had excessive water content. In these instances, official test methods were able to confirm that the fluids were within specifications.
Many popular devices measure water content based on conductivity or capacitance, which theoretically increases as water is absorbed. Typically, these devices have the following indicators:
- 0-2% water content: No need to change the brake fluid.
- 2-3% water content: An exclamation mark appears, indicating the need to change the brake fluid soon.
- 3% water content: An “X” is displayed, and an alarm sounds, signalling the immediate need to change the brake fluid to ensure safety.
Other tools convert measurements to an estimated boiling point, and use green, yellow, or red lights to indicate the result based on conductivity.
However, the conductivity of brake fluids can vary significantly between different types and formulations. Therefore, these devices can only provide accurate readings if calibrated for specific manufacturers’ products. If a fluid from an unlisted manufacturer is tested, the results may be inaccurate.
Devices that heat the fluid sample to determine the boiling point can avoid issues related to varying conductivities. Nevertheless, it is essential to ensure that this equipment is well-maintained, correctly handled, and regularly calibrated.
In cases of disputes regarding the water content or boiling points of brake fluids, it is advisable to send a sealed sample to a specialised brake fluid laboratory for testing using the Karl Fischer method.
Conclusion
Relying solely on handheld devices, especially conductivity meters, can be dangerous and potentially life-threatening if they provide incorrect measurements. Testing the boiling point remains the approved method for assessing brake fluids.
